Learn About Aquarium Power Filters

Tank-mounted power filters are usually the first step a beginner takes toward upgrading his 10-20 gallon undergravel filter. It is an important addition to a growing and maturing tank that houses more fish and more biological waste.

They can be used as the primary filtration in smaller tanks or as a secondary filter to expand the fish-keeping capacity of your tank

Power filters usually hang on the outside (back) of the tank with a drop-tube inside the tank that pulls water from the inside up into the filter, passes it over one or two cartridges which trap the particulates of excess food and feces (mechanical filtration) and then remove some organic compounds and discolorations with a carbon-filled cartridge (chemical filtration).

Power filters offer an easy and efficient means to filter your water. They can be used as the primary filtration in smaller tanks or added as a secondary filter to expand the fish-keeping capacity of your tank. However, they are not usually sufficient as a total-filtering device unless they are augmented by an additional device to provide more biological filtration.

Replaceable mechanical and chemical cartridges make power filters easy to use.

Filter cartridges not only filter the debris and some toxins from the tank, they also provide a surface area for bacteria to grow and biological activity to take place. Colonies of beneficial bacteria clean the water of biological contaminates such as Ammonia (biological filtration), although this function is poorly achieved if this is the total filtration for the tank.

After passing through the cartridges, cleansed water cascades from the filter back into the tank, agitating the surface and oxygenating the water on its way back to the aquarium.

Some newer and more sophisticated power filters now include bio-wheels or other devices separate from the cartridges. These expand the biological filtering capabilities of the filter, making it more suitable as a stand-alone aquarium filter.

Power filters are generally not very expensive compared to other types of filters. It makes them a perfect step-up (later to be used as a supplemental or secondary filter when you purchase a more sophisticated filter)

The main drawback to power filters is that they are rarely adequate for a large tank or for the more advanced hobbyist as a stand-alone unit. Additionally, they are not very attractive hanging off your aquarium, even if they are in the back. If the power filter is too deep, it will also require that the tank be moved forward from the wall, which might be undesirable.

A heavily populated tank needs much more biological filtration than a sparsely populated tank because it produces more waste. Also, as your tank matures, the load grows. A saltwater aquarium needs considerably more efficient biological filtration than a freshwater tank needs because its inhabitants are infinitely more sensitive to environmental toxins. An aquarium Power Filter is a good start, but more will be needed as your tank and fish population grows.